(1) Field of the Invention
This invention relates to inductor devices and, more particularly, to inductor devices molded of conductive loaded resin-based materials comprising micron conductive powders, micron conductive fibers, or a combination thereof, homogenized within a base resin when molded. This manufacturing process yields a conductive part or material usable within the EMF or electronic spectrum(s).
(2) Description of the Prior Art
Inductors and inductive devices are widely used in the fields of communication, radio transmission and reception, power conversion, magnetism, metal detection, and the like. All conductors exhibit some value of an inductance. Inductance is a measure of the ability of a conductor to generate electromotive force (EMF) due to a change in current. Current moving in a conductor generates a magnetic field surrounding the conductor. If the current in the conductor changes, then the magnetic field generated by that current also changes. This changing magnetic field further creates a relative motion between the magnetic field and the conductor. This relative motion further creates an induced (EMF) that is in a direction that will oppose the very current change that causes it. This is called a counter EMF. The basic unit of measure for inductance is the Henry (H) where an inductor has a value of 1 H if an EMF of 1 Volt is induced in that inductor when the current flowing through the inductor changes at a rate of 1 Ampere per second.
It is well known that if a conductor is shaped into a loop, then the electromagnetic field of any part of the loop will cut across, or be coupled to, some other part of the loop. As a result, the effective inductance of the conductor is increased by looping, or coiling, the conductor. Further, it is known that the number of turns of such a coil determines the relative inductance of this coupling. Further yet, the introduction of a core material inside of an inductor coil is known to alter the relative inductance of the conductor and, more particularly, the inductance can be increased by increasing the permeability of this coil. Coils of significant value are created by using any or all of these known factors of the core and/or the number of turns of the conductor around the core. Typical coils in the art are constructed of metal wire, such as copper, wound around core material, such as iron. In electrical systems, this inductance is used for applications such as the temporary storage of electrical energy, the creation of an inductor-capacitor network to thereby generate a resonance frequency response, and/or the transformation or isolation of voltage signals. A particularly important object of the present invention is to create inductors and/or inductive devices with improved features and from alternative materials.
Several prior art inventions relate to inductors, inductive loops, and inductive-based detectors. U.S. Pat. No. 5,247,297 to Seabury et al describes a method to detect motor vehicles crossing a loop inductor. U.S. Pat. No. 5,808,562 to Bailleul et al discloses a vehicle detector for roadway installation. The detector comprises a coaxial detector cable that further comprises a metallic central conductor, a metallic cladding, and a filler material therebetween. U.S. Pat. to No. 5,652,577 to Frasier describes an inductive loop sensing apparatus for controlling a traffic light. U.S. Pat. No. 5,969,528 to Weaver, U.S. Pat. No. 4,345,208 to Wilson, and U.S. Pat. No. 4,862,316 to Smith et al teach a portable metal detector device with transmitting and receiving coils of metal wire. U.S. Patent Application 2001/0035297 to Tamai teaches an electric wire or flat cable where the core wire or conductor comprises a highly conductive resin. The highly conductive resin may comprise a metal fiber in a thermoplastic resin. Alternatively, the highly conductive resin may comprise a lead-free solder or a copper powder dispersed in a thermoplastic resin.